Food strorage apparatus and method for controlling the same

ABSTRACT

A food storage apparatus to sterilize bacteria living in food and a method of controlling the same. The method includes starting an ordered fermentation (maturing) operation in response to a user&#39;s input including setting of a target degree of fermentation, detecting a present degree of fermentation of food stored in a storage container, and applying electric energy to the food stored in the storage container if the present degree of fermentation of the food reaches the target degree of fermentation set by the user, to sterilize fermentation fungi, and consequently, to restrict further fermentation of the food.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2006-0016947, filed on Feb. 21, 2006, in the Korean Intellectual Property Office, Korean Application No. 10-2006-0016948, filed Feb. 21, 2006 in the Korean Intellectual Property Office and Korean Application No. 10-2006-0016949, filed on Feb. 21, 2006 in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a food storage apparatus and a method of controlling the same, and, more particularly, to a food storage apparatus to store food in a fresh state for a long period, and a method of controlling the same.

2. Description of the Related Art

Food storage apparatuses store food in a fresh state for a long period. A representative example of a food storage apparatus is a refrigerator. Recently, refrigerators have been developed to include certain products for storing specific foods or articles. Examples of such products include a “Kim-chi refrigerator” to store Kimchi as a Korean representative fermented food, and the like, and a “Cosmetics refrigerator” to preserve cosmetics for a long period.

In the case of food, it may be processed in a state wherein bacteria living in soil, etc. have infiltrated raw food when the raw food was grown in the soil, and thus, part of the bacteria may still remain in the processed food.

In particular, fermented food may be excessively fermented (matured) during a storage period thereof because the propagation speed of lactobacillus, etc. can increase due to a variation of surrounding environment. Also, if a storage container is frequently opened to take out some of the fermented food stored therein, the fermented food may suffer from secondary contamination by aerobic bacteria as it is exposed to the air.

SUMMARY OF THE INVENTION

Therefore, it is an aspect of the present invention to solve the above and/or other problems.

It is an aspect of the invention to provide a food storage apparatus and a method of controlling the same, which can appropriately maintain the degree of fermentation of food stored therein at a desired level by generating a sterilizing power corresponding to the degree of fermentation of the food in association with the sterilization of bacteria living in the food.

It is another aspect of the present invention to provide a food storage apparatus and a method of controlling the same, which can prevent excessive fermentation (maturing) of food by restricting propagation of bacteria such as lactobacillus or lactic acid bacteria participating in the fermentation of food.

It is another aspect of the present invention to provide a food storage apparatus and a method of controlling the same, which can prevent secondary contamination by aerobic bacteria that may be generated when food is taken out of a storage container and exposed to the outside.

It is still another aspect of the present invention to provide a food storage apparatus and a method of controlling the same, which can ensure sterilization of raw food prior to being processed, thereby achieving sanitary food manufacture.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

The forgoing, and/or other aspects are achieved by providing a food storage apparatus comprising at least one storage container, wherein electric energy in the form of electric current is applied to food stored in the storage container, to enable sterilization of the food.

The apparatus may further comprise at least two first electrode units provided at the storage container and adapted to transmit the electric energy in the form of electric current to the food stored in the storage container.

The apparatus may further comprise: at least one storage chamber provided with at least two second electrode units and configured to receive the storage container, and the at least two second electrode units may come into contact with the at least two first electrode units, respectively, to achieve electric connection therebetween if the storage container is put into the storage chamber, thereby allowing the electric current to flow through the food inside the storage container.

Each of the at least two second electrode units may include: an electrode housing; an elastic member seated in the electrode housing while being fixed at a first end thereof to the electrode housing; and a first electrode fixed to a second end of the elastic member while protruding outward from an entrance of the electrode housing, and, if an external force is applied to the first electrode, the first electrode may be inserted into the electrode housing as the elastic member is compressed.

The apparatus may further comprise: a door to open and close the storage chamber; a door sensor to detect the opening and closing of the door; a power source to supply electric power to the at least two first electrode units; a switch provided on a conductive path defined between the power source and the at least two first electrode units; and a controller to turn off the switch if the door sensor detects the opening of the door, so as to intercept the supply of electric power from the power source to the at least two first electrode units.

Each of the at least two first electrode units may include: a second electrode mounted to come into contact with an outer wall surface of the storage container, to come into contact with a respective one of the first electrodes; and a third electrode mounted to come into contact with an inner wall surface of the storage container; and the second and third electrodes may be coupled to each other by passing through a hole perforated through the storage container, to be fixedly mounted to the storage container at the outside and inside of the storage container, respectively.

The apparatus may further comprise a controller to control the electric current, wherein a sterilizing operation mode to sterilize the food stored in the storage container may be programmed into the controller.

The apparatus may further comprise: a display device and/or speaker to inform a user of completion of sterilization if the food stored in the storage container is completely sterilized.

In accordance with another aspect, the present invention provides a food storage apparatus comprising at least one storage container, wherein electric energy in the form of an electric field is applied to food stored in the storage container, to enable sterilization of the food.

The apparatus may further comprise: at least one storage chamber to receive the storage container; and one or more electrode units to create the electric field in an interior space of the storage chamber.

The apparatus may further comprise: a door to open and close the storage chamber; a door sensor to detect the opening and closing of the door; a power source to supply electric power to the one or more electrode units; a switch provided on a conductive path between the power source and the one or more electrode units; and a controller to turn off the switch if the door sensor detects the opening of the door, so as to intercept the supply of electric power from the power source to the one or more electrode units.

A voltage of the electric power being supplied from the power source to the one or more electrode units may be in a range from 100V to 10 kV (AC or DC).

The electrode units may include first and second electrode units in the form of a plate having a predetermined area, the first and second electrode units forming at least one pair, and being arranged at an inner wall surface of the storage chamber at positions facing each other.

The electrode units may include a storage chamber electrode mounted at a wall surface of the storage chamber and adapted to receive power, and a plate-shaped storage container electrode mounted to the storage container, whereby the storage chamber electrode and storage container electrode come into contact with each other if the storage container is put into the storage chamber, to allow the power received by the storage chamber electrode to reach the storage container electrode.

The apparatus may further comprise a controller to control the electric current, wherein a sterilizing operation mode to sterilize the food stored in the storage container is programmed into the controller.

The apparatus may further comprise: a display device and/or speaker to inform a user of completion of sterilization if the food stored in the storage container is completely sterilized.

The foregoing and/or other aspects may also be achieved by providing a method of controlling a food storage apparatus comprising: starting an ordered fermentation operation in response to a user's input including setting of a target degree of fermentation; detecting a present degree of fermentation of food stored in a storage container; and applying electric energy to the food stored in the storage container if the detected present degree of fermentation of the food reaches the set target degree of fermentation, comprising comparing the detected present degree of fermentation with the set target degree of fermentation, to sterilize fermentation fungi, and consequently, to restrict further fermentation of the food.

The detecting of the present degree of fermentation of food may comprise determining a state of fermentation gas generated from the food stored in the storage container.

The detecting of the present degree of fermentation of food may further comprise determining a content of carbon dioxide of the fermentation gas generated from the food.

The detecting of the present degree of fermentation of food may comprise determining an acidity (Ph) of the fermentation gas generated from the food.

The detecting of the present degree of fermentation of food may comprise determining an interior pressure of the storage container storing the food.

The method may further comprise: applying electric energy to the food stored in the storage container for a limited period to sterilize harmful bacteria regardless of the fermentation of the food, prior to the detecting of the present degree of fermentation of the food stored in the storage container.

The method may further comprise: informing a user of the completion of sterilization via a display device and/or speaker if the food stored in the storage container is completely sterilized.

The method may further comprise: performing a safety mode preventing the electric energy from being applied to the food stored in the storage container if a door of the food storage apparatus is opened during the ordered fermentation operation.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, of which:

FIG. 1 is a sectional view showing the configuration of a food storage apparatus according to an embodiment of the present invention;

FIG. 2 is a sectional view showing an embodiment of a storage chamber electrode unit of FIG. 1;

FIG. 3 is a sectional view showing an embodiment of a storage container electrode unit of FIG. 1;

FIG. 4 is a block diagram showing a control system of the food storage apparatus of FIG. 1;

FIG. 5 is a sectional view showing the configuration of a food storage apparatus according to another embodiment of the present invention;

FIG. 6 is a sectional view showing an embodiment of a storage container electrode unit of FIG. 5;

FIG. 7 is a flow chart showing a method of controlling the food storage apparatus according to the embodiment of the present invention of FIG. 1;

FIG. 8 is a sectional view showing the configuration of a food storage apparatus according to a further embodiment of the present invention;

FIG. 9 is a block diagram showing a control system of the food storage apparatus of FIG. 8;

FIG. 10 is a sectional view showing another embodiment of an electrode unit included in the food storage apparatus of FIG. 8;

FIG. 11 is a flow chart showing a method of controlling the food storage apparatus according to the embodiment of the present invention of FIG. 8;

FIG. 12 is a sectional view showing the configuration of a storage container and the installation position of a fermentation sensor included in a food storage apparatus according to yet another embodiment of the present invention; and

FIG. 13 is a flow chart showing a method of controlling the food storage apparatus according to the embodiment of the present invention of FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.

First, FIG. 1 is a sectional view showing the configuration of a food storage apparatus according to an embodiment of the present invention. As shown in FIG. 1, the food storage apparatus includes at least one inner case 140 internally defining a storage chamber 122 to receive at least one storage container 102, and an outer case 180 to surround the inner case 140 with a foam space 124 therebetween. The foam space 124 is filled with an insulating material. The inner case 140 has an upper opening 126 to put in or take out the storage container 102. A door 128 is provided to open and close the upper opening 126 of the inner case 140. The inner case 140 is wrapped, around an outer surface thereof, with a refrigerant pipe 130 serving as an evaporator to lower the temperature of the storage chamber 122 and a heater 138 to raise the temperature of the storage chamber 122.

A machine room 132 is provided below the inner case 140. The machine room 132 is configured to receive a compressor 134, condenser 136, and other electric elements (for example, a PCB mounted with a microcomputer, power source, and various switches, etc.). A refrigerant is compressed to have a high-temperature and high-pressure in the compressor 134, and then is converted into a liquid-phase refrigerant in the condenser 136. Subsequently, the condensed high-pressure refrigerant is depressurized while passing through a capillary tube (not shown). Thereafter, the depressurized refrigerant is instantly evaporated in the refrigerant pipe 130 serving as an evaporator, to thereby absorb surrounding heat, and consequently, lower the temperature of the surroundings. Cool air, produced during the heat absorbing process, is transmitted to the inner case 140 to keep the temperature of the storage chamber 122 at a low temperature. As a result, food stored in the storage chamber 122 can be stored in a fresh state.

Conversely, to preserve the food in the storage chamber 122 at a relatively high temperature, the heater 138 is heated to raise the temperature of the surroundings around the storage chamber 122. As the raised temperature is transferred to the storage chamber 122 through the inner case 140, the interior temperature of the storage chamber 122 can be raised.

The storage container 102 for use in the food storage apparatus as shown in FIG. 1 is provided with storage container electrode units 106 a and 106 b (i.e. first electrode units), whereas the storage chamber 122 is provided at an inner wall surface thereof with storage chamber electrode units 104 a and 104 b (i.e. second electrode units). More particularly, two storage chamber electrode units 104 a and 104 b and two storage container electrode units 106 a and 106 b are provided at each storage container 102. Positions of the storage chamber electrode units 104 a and 104 b and storage container electrode units 106 a and 106 b are determined such that the corresponding electrode units 104 a and 106 a and the corresponding electrode units 104 b and 106 b come into contact with each other, respectively, to achieve electric connection therebetween when the storage container 102 is put (inserted) into the storage chamber 122.

The storage chamber electrode units 104 and 104 b are installed to protrude inward inside the storage chamber 122 such that they come into contact with the storage container electrode units 106 a and 106 b to achieve electric connection therebetween when the storage container 102 is put into the storage chamber 122. Also, the storage chamber electrode units 104 a and 104 b are connected to the power source arranged in the machine room 132 to receive an electric power therefrom. With this arrangement, if the storage chamber electrode units 104 a and 104 b come into contact with the storage container electrode units 106 a and 106 b, respectively, to achieve electric connection therebetween in a state wherein the electric power is being supplied to the storage chamber electrode units 104 a and 104 b, a closed electric circuit is produced between the storage chamber electrode units 104 a and 104 b, food 150 inside the storage container 102, and storage container electrode units 106 a and 106 b (See FIG. 4). This is because the food 150 defines a conductive path between the storage container electrode units 106 a and 106 b. An electric energy in the form of electric current is applied to the food 150 via the closed electric circuit, to destroy the cell membrane of bacteria living in the food 150 thereby achieving sterilization of the bacteria.

FIG. 2 is a sectional view showing an embodiment of the storage chamber electrode units 104 a and 104 b of FIG. 1. Here, the storage chamber electrode units 104 a and 104 b are the same, and thus, only one storage chamber electrode unit 104 a will be explained. As shown in FIG. 2, the storage chamber electrode unit 104 a includes an electrode housing 202, an elastic spring 206 inserted in the electrode housing 202, and a protruding electrode (first electrode) 204 made of a conductive material and inserted in the electrode housing 202 at the outer side of the spring 206 to partially protrude out of the electrode housing 202. One end of the spring 206 is fixed to an inner wall surface of the electrode housing 202, and the other end of the spring 206 is fixed to the protruding electrode 204. With this fixing structure, the spring 206 and protruding electrode 204 are able to be retained in the electrode housing 202 so as not to be forced out of the electrode housing 202 by an elastic force caused when the spring 206 is extended after being compressed.

In a state wherein the storage container 102 is put into the storage chamber 122, the elastic force of the spring 206 serves to maintain a more positive contact state (electrically connected state) between the protruding electrode 204 and the associated storage container electrode unit 106 a. Also, even if the protruding electrode 204 is caught by any portion protruded from the outer lateral surface of the storage container 102 (for example, a lid, handle, or the like) in the course that the storage container 102 is put into or taken out of the storage chamber 122, the protruding electrode 204 is able to be inserted into the electrode housing 202 as the spring 206 is elastically compressed, and then, is able to be returned out of the electrode housing 202 after putting or taking the storage container 102 into or out of the storage container 102 as the spring 206 is elastically extended. Thereby, the elastic force of the spring 206 serves to prevent malfunction in the putting and taking out of the storage container 102 due to the protruding electrode 204.

An outer end portion of the protruding electrode 204 is rounded, to enable easier putting and taking out of the storage container 102.

The protruding electrode 204 is connected to an electric wire 208 for the supply of electric power. The power source (See. FIG. 4) for supplying electric power to the protruding electrode 204 is mounted in the machine room 132 of FIG. 1. The electric wire 208 is installed to reach the power source by passing through the foam space 124.

FIG. 3 is a sectional view showing an embodiment of the storage container electrode units of FIG. 1. Here, the storage container electrode units 106 a and 106 b are the same, and thus, only one storage container electric unit 106 a will be explained. As shown in FIG. 3, the storage container electrode unit 106 a is made of a conductive material, and serves as an electric connector between the interior and exterior of the storage container 102 to create a conductive path between the storage chamber electrode units 104 a and 104 b and food 150. The storage container electrode unit 106 a is divided into two parts, namely, an outer electrode (second electrode) 302 that comes into contact with an outer wall surface of the storage container 102, and an inner electrode (third electrode) 304 that comes into contact with an inner wall surface of the storage container 102. One of the outer and inner electrodes 302 and 304 is formed with a male screw, and the other one is formed with a female screw. Also, a hole 306 is perforated through the storage container 102 such that the male and female screws of the outer and inner electrodes 302 and 304 are able to be fastened to each other through the hole 306. Thereby, the outer and inner electrodes 302 and 304 are able to be coupled to each other. In this structure, it is desirable that portions where the outer and inner electrodes 302 and 304 are brought into contact with the storage container 102 be sealed to prevent leakage of the food 150 stored in the storage container 102 and to prevent exterior impurities from entering the storage container 102.

FIG. 4 is a block diagram showing a control system of the food storage apparatus of FIG. 1. As shown in FIG. 4, assuming that the food 150 received in the storage container 102 is a conductive material (for example, liquid, etc.), the food storage apparatus according to the embodiment of the present invention produces a closed electric circuit in the order of the power source 402, storage chamber electrode unit 104 a, storage container electrode unit 106 a, food 150, storage container electrode unit 106 b, and storage chamber electrode unit 104 b if the storage container 102 is put in the storage chamber 122.

To allow a user to more safely put or take the storage container 102 into or out of the storage chamber 122, a switch 404 is interposed between the power source 402 and the storage chamber electrode unit 104 a. A door sensor 408 is provided to detect whether or not the door 128 is opened. If the door 128 opens the upper opening 126 of the storage chamber 122, a controller 406 turns off the switch 404 to intercept the flow of electric current. Specifically, if the user opens the door 128 to put or take the storage container 102 into or out of the storage chamber 122, the switch 404 is turned off, and thus, no electric current flows between the storage chamber electrode units 104 a and 104 b, food 150, and storage container electrode units 106 a and 106 b. This has the effect of enabling the user to more safely put or take the storage container 102 into or out of the storage chamber 122. In addition, the food storage apparatus has a sterilizing operation mode programmed into the controller. In the sterilizing operation mode, the switch 404 is turned on to permit the flow of electric current only when the user selects the sterilizing operation mode via a user input 410, resulting in an improved convenience of use. In a switch control operation performed by the controller 406, turn-off control conditions of the switch 404 required upon the opening of the door 128 should have a priority over all other turn-on control conditions of the switch 404.

The controller 406 is connected to a display device and/or speaker 412. The display device and/or speaker 412 serve to inform the user that sterilization of the food 150 is completed. Informing the completion of sterilization using the display device and/or speaker 412 allows the user to personally confirm the completion of sterilization, and thus, increases reliability with respect to the completely sterilized food 150. Accordingly, the present food storage apparatus can achieve a remarkable increase in satisfaction of users.

FIG. 5 is a sectional view showing the configuration of a food storage apparatus according to another embodiment of the present invention. As shown in FIG. 5, the positions and number of storage chamber electrode units 504 a, 504 b, 504 c, and 504 d and the positions and shape of storage container electrode units 506 a, 506 b, 506 c, and 506 d are variable in various manners on the basis of the size of storage containers 502 a, 502 b, and 502 c and the amounts of foods 550 a and 550 b.

Specifically, when two storage containers 502 a and 502 b are stacked in two layers in the storage chamber 122 as shown in the left portion of FIG. 5, and each of the storage container electrode units 506 a and 506 b is configured to come into contact with both lateral and bottom wall surfaces of an associated one of the storage containers 502 a and 502 b, a closed electric circuit may be produced in each storage container 502 a or 502 b in the order of the power source 402, storage chamber electrode unit 504 a, storage container electrode unit 506 a, food 550 a, storage container electrode unit 506 b, and storage chamber electrode unit 504 b, even if the amount of the food 550 a is small. As a result, electric current can flow through the food 550 a.

Also, when the single storage container 502 c having a large capacity is received in the storage chamber 122 as shown in the right portion of FIG. 5, the storage container electrode units 506 c and 506 d are installed at a lower surface of the storage container 502 c, and the storage chamber electrode units 504 c and 504 d are installed at a bottom surface of the storage chamber 122. In this structure, a closed electric circuit may be produced in the order of the power source 402, storage chamber electrode unit 504 c, storage container electrode unit 506 c, food 550 b, storage container electrode unit 506 d, and storage chamber electrode unit 504 d, regardless of the amount of the food 550 b stored in the storage container 502 c. As a result, electric current can flow through the food 550 b.

FIG. 6 is a sectional view showing an embodiment of one of the storage container electrode units of FIG. 5. Here, the storage container electrode units 506 a to 506 d are the same, and thus, only one storage container electrode unit 506 a will be explained. As shown in FIG. 6, the storage container electrode unit 506 a is made of a conductive material, and serves as an electric connector between the interior and exterior of the associated storage container, for example, the storage container 502 a, to create a conductive path between the associated storage chamber electrode unit 504 a and food 550 a. The storage container electrode unit 506 a is divided into two parts, namely, an outer electrode 602 that comes into contact with an outer wall surface of the storage container 502 a, and an inner electrode 604 that comes into contact with an inner wall surface of the storage container 502 a. One of the outer and inner electrodes 602 and 604 is formed with a male screw, and the other is formed with a female screw. Also, a hole 606 is perforated through the storage container 502 a such that the male and female screws of the outer and inner electrodes 602 and 604 are able to be fastened to each other through the hole 606. As a result, the outer and inner electrodes 602 and 604 are able to be coupled to each other. In this structure, it is desirable that portions where the outer and inner electrodes 602 and 604 are brought into contact with the storage container 502 a be sealed to prevent leakage of the food stored in the storage container 502 a and to prevent exterior impurities from entering the storage container 502 a.

In the present embodiment, the inner electrode 604 has an L-shaped cross section such that the inner electrode 604 comes into contact with the lateral and bottom wall surfaces of the storage container 502 a. The inner electrode 604 is coupled to the outer electrode 602 with a bottom wall of the storage container 502 a therebetween. Such a configuration of the storage container electrode unit 506 a is used as a precaution with regard to the small amount of the food 550 a.

FIG. 7 is a flow chart showing a method of controlling the food storage apparatus according to the embodiment of FIG.1. As shown in FIG. 7, if the user selects the sterilizing operation mode via the user input 410, a sterilizing operation starts in response to the user's input (operation 702).

If the sterilizing operation starts, a safety mode is also performed to prevent electric energy from being supplied to the food 150 received in the storage container 102 as soon as the door 128 is opened (operation 704). The safety mode is continuously activated during the sterilizing operation for the sake of the user's safety.

Then, electric energy is supplied to the food 150 stored in the storage container 102 to destroy the cell membrane of harmful bacteria (microorganisms), so as to achieve sterilization of the food 150 (operation 706).

Once the electric energy is supplied to the food 150 to destroy the harmful bacteria, whether or not harmful bacteria living in the food 150 are completely sterilized is monitored (operation 708). Bacteria tend to discharge unique chemical materials during their existence. Therefore, it can be determined whether the harmful bacteria living in the food 150 are mostly destroyed by the supplied electric energy or still remain, based on the discharge of the chemical materials. If it is determined that the sterilization of the harmful bacteria is completed (as designated by the arrow “YES” in the operation 708), the display device and/or speaker 412 informs the user of the completion of sterilization (operation 710). Informing the completion of sterilization using the display device and/or speaker 412 allows the user to personally confirm the completion of sterilization of the food 150, and provides the user with reliability with respect to the completely sterilized food 150, resulting in a remarkable increase in satisfaction of users with respect to the food storage apparatus. Even after the completion of sterilization is informed, the electric energy is continuously supplied to the food 150 to continue the sterilization of harmful bacteria. This has the effect of restricting propagation of aerobic bacteria due to the opening of the storage container 102.

Then, if the user selects the end of the sterilizing operation using the user input 410, and the controller 406 receives the end command (as designated by the arrow “YES” in the operation 712), the supply of electric energy to the food 150 is intercepted in response to the user's selection, to end the sterilizing operation (operation 714).

FIG. 8 is a sectional view showing the configuration of a food storage apparatus according to a further embodiment of the present invention. As shown in FIG. 8, the food storage apparatus includes at least one inner case 840 internally defining a storage chamber 822 to receive at least one storage container 802, and an outer case 880 to surround the inner case 840 with a foam space 824 therebetween. The foam space 824 is filled with an insulating material. The inner case 840 has an upper opening 826 to put or take the storage container 802 into or out of the storage chamber 822. A door 828 is provided to open and close the upper opening 826 of the inner case 840. The inner case 840 is wrapped, around an outer surface thereof, with a refrigerant pipe 830 serving as an evaporator to lower the temperature of the storage chamber 822 and a heater 838 to raise the temperature of the storage chamber 822.

A machine room 832 is provided below the inner case 840. The machine room 832 receives a compressor 834, condenser 836, and other electric elements (for example, a PCB provided with a microcomputer, power source, and various switches, etc.). A refrigerant is compressed to have a high-temperature and high-pressure in the compressor 834, and then, is converted into a liquid-phase refrigerant in the condenser 836. Subsequently, the condensed high-pressure refrigerant is depressurized while passing through a capillary tube (not shown). Thereafter, the depressurized refrigerant is instantly evaporated in the refrigerant pipe 830 serving as an evaporator, to thereby absorb surrounding heat, and consequently, lower the temperature of the surroundings. Cool air, produced during the heat absorbing process, is transmitted to the inner case 840 to keep the temperature of the storage chamber 822 low. As a result, food stored in the storage chamber 822 can be stored in a fresh state.

Conversely, to preserve the food in the storage chamber 822 at a relatively high temperature, the heater 838 is heated to raise the temperature of the surroundings around the storage chamber 822. As the raised temperature is transferred to the storage chamber 822 through the inner case 840, the interior temperature of the storage chamber 822 can be raised.

The food storage apparatus shown in FIG. 8 is provided with one or more electrode units 804 a and 804 b to create an electric field in the storage chamber 822. The electrode units 804 a and 804 b include plate-shaped first and second electrode units having a predetermined area. The first and second electrode units 804 a and 804 b, which form a pair, are attached to an inner wall surface of the storage chamber 822 at positions facing each other. The first and second electrode units 804 a and 804 b are connected to the power source (See FIG. 9) arranged in the machine room 832 to receive electric power therefrom.

If an appropriate level of electric potential difference (for example, 100V to 10 kV (AC or DC)) is imparted between the first and second electrode units 804 a and 804 b, an electric field depending on the electric potential difference is created between the first and second electrode units 804 a and 804 b. Electric energy in the form of the electric field is applied to the food 850, to destroy the cell membranes of bacteria living in the food 850 for achieving sterilization of the food 850.

FIG. 9 is a block diagram showing a control system of the food storage apparatus of FIG. 8. As shown in FIG. 9, in the food storage apparatus, the electric field is created between the first and second electrode units 804 a and 804 b when an electric power is supplied from a power source 902 to the first and second electrode units 804 a and 804 b. To allow the user to more safely put or take the storage container 802 into or out of the storage chamber 822, a switch 904 is interposed between the power source 902 and the first electrode unit 804 a. A door sensor 908 is provided to detect whether or not the door 828 is opened. If the door 828 opens the upper opening 826 of the storage chamber 822, a controller 906 turns off the switch 904 so as not to create the electric field between the first and second electrode units 804 a and 804 b. Specifically, if the user opens the door 828 to put or take the storage container 802 into or out of the storage chamber 822, the switch 904 is turned off, and thus, no electric field is created. This has the effect of enabling the user to more safely put or take the storage container 802 into or out of the storage chamber 822. In addition, the food storage apparatus has a sterilizing operation mode. In the sterilizing operation mode, the switch 904 is turned on to permit the supply of electric power to the first electrode unit 804 a only when the user selects the sterilizing operation mode via a user input 910, resulting in an improved convenience of use. In a switch control operation performed by the controller 906, turn-off control conditions of the switch 904 required upon the opening the door 828 should have a priority over all other turn-on control conditions of the switch 904. In FIG. 9, reference numeral 914 denotes the electric field.

The controller 906 is connected to a display device and/or speaker 912. The display device and/or speaker 912 serve to inform the user of the fact that sterilization of the food 850 is completed. Informing the completion of sterilization using the display device and/or speaker 912 allows the user to personally confirm the completion of sterilization of the food 850, and provides the user with reliability with respect to whether the food 850 is completely sterilized. Accordingly, the present food storage apparatus can achieve a remarkable increase in satisfaction of users.

FIG. 10 is a sectional view showing another embodiment of the electrode units included in the food storage apparatus of FIG. 8. As shown in FIG. 10, each storage container 802 is provided with a pair of electrode units 1004 a and 1006 a.

The pair of electrode units 1004 a and 1006 a includes a storage chamber electrode 1004 a mounted at an inner wall surface of storage chamber 1022 while being connected to the power source (for example, as designated by reference numeral 902 of FIG. 9), and a plate-shaped storage container electrode 1006 a attached to an outer surface of the storage container 1002. If the storage container 1002 is put into the storage chamber 1022, the storage chamber electrode 1004 a and storage container electrode 1006 a come into contact with each other, to allow a power supplied from the power source 902 to reach the storage container electrode 1006 a by passing through the storage chamber electrode 1004 a. In this case, an electric field is created by electric potential difference between the storage container electrode 1006 a and food 1050 received in the storage container 1002. The electric field enables sterilization of bacteria living in the food 1050. The storage chamber electrode 1004 a of FIG. 10 may have the same configuration as that of FIG. 2. A foam space 1024 is filled with an insulating material.

FIG. 11 is a flow chart showing a method of controlling the food storage apparatus according to the embodiment of FIG. 9. As shown in FIG. 11, if the user selects a sterilizing operation mode via the user input 910, a sterilizing operation starts in response to the user's input (operation 1102).

If the sterilizing operation starts, a safety mode is also performed to prevent electric energy from being supplied to the food 850 stored in the storage container 802 as soon as the door 828 is opened (operation 1104). The safety mode is continuously activated during the sterilizing operation for the sake of the user's safety.

Then, electric energy is supplied to the food 850 stored in the storage container 802 to destroy the cell membrane of harmful bacteria (microorganisms), so as to achieve sterilization of the food 850 (operation 1106). To destroy almost all harmful bacteria living in the food 850, it is desirable that a time required for sterilizing 99% or more of harmful bacteria living in the food 850 be measured via an experiment, and an electric energy supply time be determined based on the experimental result.

Once the electric energy is supplied to the food 850 to destroy the harmful bacteria, whether or not harmful bacteria living in the food 850 are completely sterilized is monitored (operation 1108). Bacteria tend to discharge unique chemical materials during their existence. Therefore, it can be determined whether harmful bacteria living in the food 850 are mostly destroyed by the supplied electric energy or still remain, based on the discharge of the chemical materials. If it is determined that the sterilization of the harmful bacteria is completed (as designated by the arrow “YES” in operation 1108), the display device and/or speaker 912 informs the user of the completion of sterilization (operation 1110). Informing the completion of the sterilization using the display device and/or speaker 912 allows the user to personally confirm the completion of the sterilization of the food 850, and provides the user with reliability with respect to the completely sterilized food 850, resulting in a remarkable increase in satisfaction of users. Even after the completion of the sterilization is informed, the electric energy is continuously supplied to the food 850 to continue the sterilization of harmful bacteria. This has the effect of restricting propagation of aerobic bacteria due to the opening of the storage container 802.

Then, if the user selects the end of the sterilizing operation using the user input 910, and the controller 1106 receives the end command (as designated by the arrow “YES” in the operation 1112), the supply of electric energy to the food 850 is intercepted in response to the user's selection, to end the sterilizing operation (operation 1114).

In an experiment to confirm sterilizing effects an electric current of 0.001 A is applied at a voltage of 100V to 10 kV (AC or DC) to a colon bacilli culture solution. In accordance with the following experimental results as illustrated below, the destruction rate of colon bacilli is more than 90% after 3 hours, and more than 99% after 4 hours.

Number of living colon bacilli Destruction amount Time (hr) individuals (CFU/ml) (%) 0   3 × 10⁷ 0 1 1.2 × 10⁷ 60 2 8.3 × 10⁶ 72.3 4 3.3 × 10⁴ 99.89 6 5.2 × 10³ 99.98

FIG. 12 is a sectional view showing the configuration of a storage container and the installation position of a fermentation sensor in accordance with yet another embodiment of the present invention. As shown in FIG. 12, a storage container 1202 is perforated, through a lateral wall at a position close to an upper end thereof, with a hole having a relatively small size. The hole is closed by a permeable member 1206 made of a certain material such as GORE-TEX® to allow permeation of gas, but to prevent permeation of a liquid. Accordingly, the permeable member 1206 discharges a small amount of fermentation gas inside the storage container 1202 to the outside.

A fermentation sensor 1204 is mounted in an inner wall surface of the inner case 140 to be exposed to the storage chamber 122. The fermentation sensor 1204 is used to detect the degree of fermentation of food 1250 stored in the storage container 1202 and to detect the propagation of bacteria living in the food 1250. Accordingly, it is desirable that the fermentation sensor 1204 be mounted at a position as close as possible to the permeable member 1206 when the storage container 1202 is put into the storage chamber 122.

The fermentation sensor 1204 may be a gas sensor to detect the degree of fermentation of food based on the content of carbon dioxide of fermentation gas generated from fermented food, or may be an acidimeter sensor to detect the acidity (Ph) of fermentation gas. Also, because the interior pressure of the storage container 1202 increases in proportion to the progression of fermentation of food therein, the degree of fermentation of food can be determined as a pressure sensor detects a variation in the interior pressure of the storage container 1202.

FIG. 13 is a flow chart illustrating a method of controlling the food storage apparatus according to the embodiment of FIG. 12. As shown in FIG. 13, if the user selects an ordered fermentation (maturing) operation mode via the user input 410, an ordered fermentation (maturing) operation starts in response to the user's input (operation 1302). When selecting the ordered fermentation (maturing) operation mode via the user input 410, the user also sets a desired target degree of fermentation. Here, the target degree of fermentation may be classified into High, Middle, and Low levels, or may be classified into numbered levels ranging from 0 to 9. Of course, other various methods may be used to classify the target degree of fermentation.

If the ordered fermentation (maturing) operation starts, a safety mode is also performed to prevent electric energy from being supplied to the food 1250 stored in the storage container 1202 as soon as the door 128 is opened (operation 1304). The safety mode is continuously activated during the ordered fermentation (maturing) operation for the sake of the user's safety.

Meanwhile, prior to starting the ordered fermentation (maturing) operation of the food 1250 stored in the storage container 1202 (namely, in the early stage of storage), electric energy is supplied to the food 1250 for a limited period to destroy harmful bacteria that may live in the food 1250 (operation 1306). In this case, it should be noted that, if the electric energy is supplied to the food 1250 indefinitely, it may prevent propagation of beneficial fungi (for example, lactobacillus or lactic acid bacteria, etc.) participating in the fermentation of the food 1250. Therefore, it is desirable that the supply of electric energy for the sterilization of harmful bacteria be performed only for a limited period, and then, be stopped to allow the propagation of the fermentation fungi (operation 1308).

If the supply of electric energy to the food 1250 is stopped, the fermentation fungi starts to propagate, to progress fermentation (maturing) of the food 1250. Accordingly, once the supply of electric energy to the food 1250 is intercepted, whether or not the present fermentation (maturing) amount of the food 1250 reaches the preset target fermentation amount is monitored (operation 1310). If the present fermentation amount of the food 1250 does not reach the target fermentation amount (as designated by the arrow “No” in the operation 1310), the supply of electric energy is continuously intercepted, to allow the fermentation fungi to continue propagation thereof, and thus, to achieve further fermentation (maturing) of the food 1250. Conversely, if the present fermentation amount of the food 1250 reaches the target fermentation amount (as designated by the arrow “YES” in the operation 1310), the supply of electric energy to the food 1250 is initiated to sterilize the fermentation fungi, so as to prevent further fermentation (maturing) of the food 1250 (operation 1312). In this way, initiating the supply of electric energy to the food 1250 causes sterilization of almost all fermentation fungi as well as harmful bacteria, resulting in an interruption in the fermentation of the food 1250.

After the supply of electric energy to the food 1250 is initiated, whether or not the fermentation fungi living in the food 1250 are completely sterilized is monitored (operation 1314). Bacteria including the fermentation fungi tend to discharge unique chemical materials during their existence. Therefore, it can be determined whether the fermentation fungi living in the food 1250 are mostly destroyed by the supplied electric energy or still remain, based on the discharge of the chemical materials. If it is determined that the sterilization of the fermentation fungi is completed (as designated by the arrow “YES” in the operation 1314), the display device and/or speaker 412 informs the user of the completion of sterilization (operation 1316). Informing the completion of sterilization using the display device and/or speaker 412 allows the user to personally confirm the completion of sterilization, and provides the user with assurance with respect to the completely sterilized food 1250, resulting in a remarkable increase in satisfaction of users with respect to the food storage apparatus. Even after the completion of sterilization is informed, the electric energy is continuously supplied to the food 1250 to continue sterilization of the fermentation fungi. This has the effect of restricting further fermentation of the food 1250, and preventing propagation of aerobic bacteria caused when the food 1250 is exposed to the air via the opening of the storage container 1202.

Then, if the user selects the end of the ordered fermentation (maturing) operation using the user input 410, and the controller 406 receives the end command (as designated by the arrow “YES” in the operation 1318), the supply of electric energy to the food 1250 is intercepted in response to the user's selection, to end the ordered fermentation (maturing) operation (operation 1320).

With the use of the present food storage apparatus and method of controlling the same, accordingly, sterilization of bacteria living in raw food prior to being processed can be accomplished.

As apparent from the above description, the embodiments of the present invention provide the following effects.

First, a food storage apparatus is designed to apply electric energy, in the form of electric current, to food stored in a storage container, so as to destroy the cell membrane of microorganisms living in the food, and consequently, sterilize the food. This has the effect of maintaining the food in a fresh state for a long period.

In particular, in addition to sterilizing harmful bacteria, the present food storage apparatus has a function of sterilizing lactobacillus or lactic acid bacteria participating in fermentation of food if necessary, so as to restrict excessive maturing (or fermentation) of food. This enables the freshness of food to be kept at a target level.

Furthermore, the present embodiments prevent secondary contamination by aerobic bacteria that may be caused when food is exposed to the air in the course of being taken out of the storage container.

Finally, the present embodiments enable sterilization of raw materials prior to being processed, resulting in more sanitary food manufacture.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art-that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A food storage apparatus comprising at least one storage container, wherein electric energy in the form of electric current is applied to food stored in the storage container, to enable sterilization of the food.
 2. The apparatus according to claim 1, further comprising: at least two first electrode units provided at the storage container and adapted to transmit the electric energy in the form of electric current to the food stored in the storage container.
 3. The apparatus according to claim 2, further comprising: at least one storage chamber provided with at least two second electrode units and configured to receive the storage container, wherein the at least two second electrode units come into contact with the at least two first electrode units, respectively, to achieve electric connection therebetween if the storage container is put into the storage chamber, thereby allowing the electric current to flow through the food inside the storage container.
 4. The apparatus according to claim 3, wherein each of the at least two second electrode units includes: an electrode housing; an elastic member seated in the electrode housing while being fixed at a first end thereof to the electrode housing; and a first electrode fixed to a second end of the elastic member while protruding outward from an entrance of the electrode housing, wherein, if an external force is applied to the first electrode, the first electrode is inserted into the electrode housing as the elastic member is compressed.
 5. The apparatus according to claim 3, further comprising: a door to open and close the storage chamber; a door sensor to detect the opening and closing of the door; a power source to supply electric power to the at least two first electrode units; a switch provided on a conductive path defined between the power source and the at least two first electrode units; and a controller to turn off the switch if the door sensor detects the opening of the door, so as to intercept the supply of electric power from the power source to the at least two first electrode units.
 6. The apparatus according to claim 4, wherein each of the at least two first electrode units includes: a second electrode mounted to come into contact with an outer wall surface of the storage container, and to come into contact with a respective one of the first electrodes; and a third electrode mounted to come into contact with an inner wall surface of the storage container, wherein the second and third electrodes are coupled to each other by passing through a hole perforated through the storage container, to be fixedly mounted to the storage container at the outside and inside of the storage container, respectively.
 7. The apparatus according to claim 1, further comprising a sterilizing operation mode to sterilize the food stored in the storage container.
 8. The apparatus according to claim 1, further comprising: a display device and/or speaker to inform a user of completion of sterilization if the food stored in the storage container is completely sterilized.
 9. A food storage apparatus comprising at least one storage container, wherein electric energy in the form of an electric field is applied to food stored in the storage container, to enable sterilization of the food.
 10. The apparatus according to claim 9, further comprising: at least one storage chamber to receive the storage container; and one or more electrode units to create the electric field in an interior space of the storage chamber.
 11. The apparatus according to claim 10, further comprising: a door to open and close the storage chamber; a door sensor to detect the opening and closing of the door; a power source to supply electric power to the one or more electrode units; a switch provided on a conductive path between the power source and the one or more electrode units; and a controller to turn off the switch if the door sensor detects the opening of the door, so as to intercept the supply of electric power from the power source to the one or more electrode units.
 12. The apparatus according to claim 11, wherein a voltage of the electric power being supplied from the power source to the one or more electrode units is in a range from 100V to 10 kV, AC or DC.
 13. The apparatus according to claim 10, wherein the electrode units include first and second electrode units in the form of a plate having a predetermined area, the first and second electrode units forming at least one pair, and being arranged at an inner wall surface of the storage chamber at positions facing each other.
 14. The apparatus according to claim 10, wherein the electrode units include a storage chamber electrode mounted at a wall surface of the storage chamber and adapted to receive power, and a plate-shaped storage container electrode mounted to the storage container, and the storage chamber electrode and storage container electrode come into contact with each other if the storage container is put into the storage chamber, to allow the power received by the storage chamber electrode to reach the storage container electrode.
 15. The apparatus according to claim 9, further comprising a sterilizing operation mode to sterilize the food stored in the storage container.
 16. The apparatus according to claim 9, further comprising: a display device and/or speaker to inform a user of completion of sterilization if the food stored in the storage container is completely sterilized.
 17. A method of controlling a food storage apparatus comprising: starting an ordered fermentation operation in response to a user's input including setting of a target degree of fermentation; detecting a present degree of fermentation of food stored in a storage container; and applying electric energy to the food stored in the storage container if the detected present degree of fermentation of the food reaches the set target degree of fermentation, comprising comparing the detected present degree of fermentation with the set target degree of fermentation, to sterilize fermentation fungi, and consequently, to restrict further fermentation of the food.
 18. The method according to claim 17, wherein the detecting of the present degree of fermentation of food comprises determining a state of fermentation gas generated from the food stored in the storage container.
 19. The method according to claim 18, wherein the detecting of the present degree of fermentation of food further comprises determining a content of carbon dioxide of the fermentation gas generated from the food.
 20. The method according to claim 18, wherein the detecting of the present degree of fermentation of food comprises determining an acidity of the fermentation gas generated from the food.
 21. The method according to claim 18, wherein the detecting of the present degree of fermentation of food comprises determining an interior pressure of the storage container storing the food.
 22. The method according to claim 17, further comprising: applying electric energy to the food stored in the storage container for a limited period to sterilize harmful bacteria regardless of the fermentation of the food, prior to the detecting of the present degree of fermentation of the food stored in the storage container.
 23. The method according to claim 17, further comprising: informing a user of the completion of sterilization via a display device and/or speaker if the food stored in the storage container is completely sterilized.
 24. The method according to claim 17, further comprising: performing a safety mode preventing the electric energy from being applied to the food stored in the storage container if a door of the food storage apparatus is opened during the ordered fermentation operation.
 25. A food storage apparatus comprising at least one storage container, wherein electric energy is applied to food stored in the storage container, to enable sterilization of the food.
 26. A method of controlling a food storage apparatus comprising: detecting a present degree of fermentation of food stored in a storage container; and applying electric energy to the food stored in the storage container if the detected present degree of fermentation of the food reaches a set target degree of fermentation. 